<template>
  <div class="standard-table">
    <div class="alert">
      <a-alert type="info" :show-icon="true" v-if="selectedRows">
        <div class="message" slot="message">
          已选择&nbsp;
          <a>{{ selectedRows.length }}</a>
          &nbsp;项
          <a class="clear" @click="onClear">清空</a>
          <template v-for="(item, index) in needTotalList">
            <div v-if="item.needTotal" :key="index">
              {{ item.title }}总计&nbsp;
              <a>
                {{
                  item.customRender ? item.customRender(item.total) : item.total
                }}
              </a>
            </div>
          </template>
        </div>
      </a-alert>
    </div>
    <a-table
      :bordered="bordered"
      :loading="loading"
      :columns="columns"
      :dataSource="dataSource"
      :rowKey="rowKey"
      :pagination="pagination"
      :expandedRowKeys="expandedRowKeys"
      :expandedRowRender="expandedRowRender"
      @change="onChange"
      :rowSelection="
        selectedRows
          ? { selectedRowKeys: selectedRowKeys, onChange: updateSelect }
          : undefined
      "
    >
      <template
        slot-scope="text, record, index"
        :slot="slot"
        v-for="slot in Object.keys($scopedSlots).filter(
          (key) => key !== 'expandedRowRender'
        )"
      >
        <slot :name="slot" v-bind="{ text, record, index }"></slot>
      </template>
      <template :slot="slot" v-for="slot in Object.keys($slots)">
        <slot :name="slot"></slot>
      </template>
      <template
        slot-scope="record, index, indent, expanded"
        :slot="$scopedSlots.expandedRowRender ? 'expandedRowRender' : ''"
      >
        <slot
          v-bind="{ record, index, indent, expanded }"
          :name="$scopedSlots.expandedRowRender ? 'expandedRowRender' : ''"
        ></slot>
      </template>
    </a-table>
  </div>
</template>

<script>
  export default {
    name: 'StandardTable',
    props: {
      bordered: Boolean,
      loading: [Boolean, Object],
      columns: Array,
      dataSource: Array,
      rowKey: {
        type: [String, Function],
        default: 'key',
      },
      pagination: {
        type: [Object, Boolean],
        default: true,
      },
      selectedRows: Array,
      expandedRowKeys: Array,
      expandedRowRender: Function,
    },
    data() {
      return {
        needTotalList: [],
      }
    },
    methods: {
      updateSelect(selectedRowKeys, selectedRows) {
        this.$emit('update:selectedRows', selectedRows)
        this.$emit('selectedRowChange', selectedRowKeys, selectedRows)
      },
      initTotalList(columns) {
        const totalList = columns
          .filter((item) => item.needTotal)
          .map((item) => {
            return {
              ...item,
              total: 0,
            }
          })
        return totalList
      },
      onClear() {
        this.updateSelect([], [])
        this.$emit('clear')
      },
      onChange(pagination, filters, sorter, { currentDataSource }) {
        this.$emit('change', pagination, filters, sorter, { currentDataSource })
      },
    },
    created() {
      this.needTotalList = this.initTotalList(this.columns)
    },
    watch: {
      selectedRows(selectedRows) {
        this.needTotalList = this.needTotalList.map((item) => {
          return {
            ...item,
            total: selectedRows.reduce((sum, val) => {
              let v
              try {
                v = val[item.dataIndex]
                  ? val[item.dataIndex]
                  : eval(`val.${item.dataIndex}`)
              } catch (_) {
                v = val[item.dataIndex]
              }
              v = !isNaN(parseFloat(v)) ? parseFloat(v) : 0
              return sum + v
            }, 0),
          }
        })
      },
    },
    computed: {
      selectedRowKeys() {
        return this.selectedRows.map((record) => {
          return typeof this.rowKey === 'function'
            ? this.rowKey(record)
            : record[this.rowKey]
        })
      },
    },
  }
</script>

<style scoped lang="less">
  .standard-table {
    .alert {
      margin-bottom: 16px;
      .message {
        a {
          font-weight: 600;
        }
      }
      .clear {
        float: right;
      }
    }
  }
</style>
